Gruber Michael, Uffmann Martin, Weber Michael, Prokop Mathias, Balassy Csilla, Schaefer-Prokop Cornelia
Department of Radiology and Ludwig Boltzmann-Institute for Clinical and Experimental Radiologic Research, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
Eur Radiol. 2006 Jul;16(7):1544-50. doi: 10.1007/s00330-005-0077-1. Epub 2006 Jan 11.
The image quality of dual-reading computed radiography and dose-reduced direct radiography of the chest was compared in a clinical setting. The study group consisted of 50 patients that underwent three posteroanterior chest radiographs within minutes, one image obtained with a dual read-out computed radiography system (CR; Fuji 5501) at regular dose and two images with a flat panel direct detector unit (DR; Diagnost, Philips). The DR images were obtained with the same and with 50% of the dose used for the CR images. Images were evaluated in a blinded side-by-side comparison. Eight radiologists ranked the visually perceivable difference in image quality using a three-point scale. Then, three radiologists scored the visibility of anatomic landmarks in low and high attenuation areas and image noise. Statistical analysis was based on Friedman tests and Wilcoxon rank sum tests at a significance level of P<0.05. DR was judged superior to CR for the delineation of structures in high attenuation areas of the mediastinum even when obtained with 50% less dose (P<0.001). The visibility of most pulmonary structures was judged equivalent with both techniques, regardless of acquisition dose and speed level. Scores for image noise were lower for DR compared with CR, with the exception of DR obtained at a reduced dose. Thus, in this clinical preference study, DR was equivalent or even superior to the most modern dual read-out CR, even when obtained with 50% dose. A further dose reduction does not appear to be feasible for DR without significant loss of image quality.
在临床环境中比较了胸部双读计算机X线摄影和低剂量直接X线摄影的图像质量。研究组由50名患者组成，这些患者在数分钟内接受了三张后前位胸部X线片检查，一张是使用常规剂量的双读出计算机X线摄影系统（CR；富士5501）获得的图像，另外两张是使用平板直接探测器单元（DR；飞利浦Diagnost）获得的图像。DR图像分别使用与CR图像相同的剂量以及CR图像剂量的50%获得。图像在双盲并排比较中进行评估。八位放射科医生使用三点量表对图像质量的视觉可感知差异进行排名。然后，三位放射科医生对低衰减和高衰减区域的解剖标志的可见性以及图像噪声进行评分。统计分析基于Friedman检验和Wilcoxon秩和检验，显著性水平为P<0.05。即使使用少50%的剂量获得图像，在纵隔高衰减区域结构的描绘方面，DR被判定优于CR（P<0.001）。无论采集剂量和速度水平如何，两种技术在大多数肺部结构的可见性方面被判定相当。与CR相比，DR的图像噪声评分更低，但剂量减少时获得的DR图像除外。因此，在这项临床偏好研究中，即使使用50%的剂量，DR与最现代的双读出CR相当甚至更优。对于DR来说，在不显著损失图像质量的情况下进一步降低剂量似乎不可行。
